Fuel injector



United States Patent Neville ll. Reiners;

Julius P. Pen, Columbus, Indiana 788,387

Jan. 2 -1969 Dec. 1, 1970 Cummins Engine Company, Inc. Columbus, Indianaa corporation of Indiana Inventors App]. No. Filed Patented AssigneeFUEL INJECTOR .21 Claims, 18 DrawingFigs. I

U.S.-Cl

239/ 90,. 239/533 Int. Cl ..F02m 47/02 [50] Field ofSearch ..239/533, 90

[5 6] References Cited UNITED STATESPATENTS 3,351,288 11/1967 PerrPrimary Examiner-Lloyd L. King Assistant Examiner-Gene A. ChurchAttorney-Hibben, Noyes & Bicknell ABSTRACT: A fuel injector forinjecting fuel into a cylinder of an internal combustion engine, whereinthe maximum stroke of a shiftable piston in the injector determinesthe-maximum quantity of fuel injected by the injector during each cycleof operation thereof.

Patefited D.1," 197o 3,544,008

Sheet 1 of? Iva/@7215 r55 Neville HReL'nerb, 104 Julius PPerr 165 5 Wan/M Patented Dec. 1, 1970 3,544,008

Sheet 3 of? Patented Dec. 1, 197 0 Sheet 3; of 7 we 5 21 Z267 229 l 9.2256 H7 232 .197 vi 196 -254 g w A .l 2.34 286 1a .53 J99 FUEL INJECTORThis invention relates to a fuel injector for internal combustionengines, and more particularly to a fuel injector wherein the maximumquantity of fuel delivered by the injector is limited.

One of the problems experienced by manufacturers of internal combustionengines is that of increased warranty expenses due to premature failureof major engine components. Such premature failure is attributable, inmany instances, to tampering with or unauthorized modification of thefuel system of the engine by the user to cause overfueling and thusincrease the maximum power output of the engine above its normal rating.Such practice is also undesirable for other reasons, namely, theproduction of excessive exhaust smoke and loss of or erratic throttleresponse. Consequently, in addition to increasing the warranty expensesof the engine manufacturer, the aforementioned practice is alsoundesirable from an air pollution and safety standpoint.

Accordingly, his a general object of the invention to provide a novelfuel injector for supplying fuel to an internal combustion engine, whichcannot be tampered with by modifying or altering to cause overfueling.

Another object is to provide a novel fuel injector for use in a fuelsupply system for an internal combustion engine, wherein the maximumquantity of fuel delivered by the injector is unaffected by abnormaladjustments or modifications of other parts of the system.

A more particular object is to provide a novel fuel injector having apiston shiftably mounted therein, wherein the maximum stroke of thepiston determines the maximum quantity of fuel injected by the injector.

Still another object is to provide a novel fuel injector of theforegoing character, which cannot be easily dismantled or tampered withto increase the quantity of fuel delivered thereby above a predeterminedmaximum.

Other objects and advantages will become apparent from the followingdetailed description and accompanying drawings, wherein:

FIG. 1 is a fragmentary cross-sectional view of a portion of an internalcombustion engine including a fuel injector embodying the features ofthe invention;

FIG. 2 is an enlarged longitudinal sectional view of the injectorillustrated in FIG. 1, with some parts shown in elevation and withportions thereof shown broken away, taken substantially along the line2-2 of FIG. ;1;

FIG. 3 is a transversesectional view taken along the line 3-3 of FIG. 2;I

FIG. 4 is a fragmentary longitudinal sectional view taken along the line4-4 of FIG. '3; 7

FIG. 5 is a transverse sectional view taken along the line 5- of FIG. 4;

FIG. 6 is a longitudinal sectional view taken along the line 6-6 of FIG.3;

FIG. 7 is a longitudinal sectional view, similar to FIG. 2, but showingcertain parts of the injector in a different position;

FIG. 8 is a fragmentary longitudinal sectional view, similar' to FIG. 4,but showing certain parts of the injector in a different position;

FIG. 9 is a longitudinal sectional view, with some parts shown inelevation, of another injector embodying the features of the invention;

FIG. 10 is a transverse sectional view taken along the line 10-10 ofFIG.9;

FIG. 11 is a fragmentary longitudinal sectional view, taken along theline 11-11 of FIG. 10, of the upper portion of the injector illustratedin FIG. 9;

FIG. 12 is a fragmentary longitudinal sectional view, taken along theline 12-12 of FIG. 10;

FIG. 13 is a fragmentary longitudinal sectional view, similar to FIG. 9,but showing certain parts of the injector in different positions;

FIG. 14 is a longitudinal sectional 'view, similar to FIG. 12, butshowing certain parts of the injector in different positions;

FIG. 15 is a longitudinal sectional view, with some parts in elevation,of another injector embodying the features of the invention;

FIG. 16 is a view similar to FIG. 15, but showing certain parts of theinjector in different positions;

FIG. 17 is a transverse sectional view taken along the line 17-17 ofFlG.16; and

FIG. 18 is a fragmentary longitudinal sectional view. taken along theline 18-18 of FIG. 17, of the upper portion of the injector illustratedin FIGS. 15 and 16.

Briefly described, the present invention contemplates a novel fuelinjector for use in a fuel supply system for an internal combustionengine of the diesel type. A system with which the present injector isadapted for use is disclosed and claimed in US. Pat. No. 3,159,152,issued Dec. l, 1964 to Reiners. The injector contemplated herein has anelongated body having a plunger bore therein and a plunger reciprocablymounted in the bore. A fuel injection chamber at the end of the body forreceiving a quantity of fuel is provided, the fuel being injected by theplunger into an associated cylinder of the engine through a nozzle atone end of the body.

The injector body also includes a fuel passage adapted to be connectedat one end to a source of fuel under pressure and having a connectionwith the fuel injection chamber and another connection connected to adrain. The plunger is operable when in one position to establish a flowthrough the fuel passage from the source to the other connection andthus to drain. The plunger is also operable when in another 0 positionto interrupt flow through the other connection and to establish flowthrough the first mentioned connection to the fuel injection chamber.

The fuel injector to be hereinafter described in detail also includesnovel means for limiting the maximum quantity of fuel capable of beingsupplied to the fuel injection chamber for injection into the associatedcylinder. Such means preferably comprises cylinder means constitutingpart of a branch portion of the fuel passage, and a piston mounted inthe cylinder means. The piston is shiftable in the cylinder means anddefines a fuel limiting chamber at one side thereof having a volumewhich varies with the stroke of the piston. The arrangement is such thatduring one portion of the operating cycle of the injector, the piston ismoved by the pressure of the fuel supplied to the injector in adirection to create the fuel limiting chamber and till the chamber withfuel. During another portion of the operating cycle of the injector, thepressure of the fuel is utilized to move the piston in the oppositedirection to transfer a quantity of fuel into the fuel injection chamberequal to that in the fuel limitingchamber. The maximum stroke of thepiston is limited and therefore the maximum volume of the fuel limitingchamber is limited. Consequently, the maximum quantity of fuel that canbe injected by the injector during any one cycle of operation is alsolimited, regardless of the pressure of the fuel supplied to the injectorfrom the source or the degree of restriction of the flow to drain.

In FIG. I, a fragment of a multicylinder internal combustion engine, inthis instance, a diesel engine, is illustrated. Such engine comprises acylinder block 21 having a plurality of cylinders provided withreciprocable pistons. Only a portion of one cylinder 22 and one piston23 are shown in FIG. 1.

The fragment of the engine illustrated in FIG. 1 also includes acylinder head 24 mounted on the block 21 and having stepped injectormounting bores 26 therein, one for each of the respective cylinders. Afuel injector 30, embodying the features of the invention, is mounted ineach of the bores 26.

The cylinder head 24 may also be provided with a pair of Iongitudinallyextending, vertical spaced bores 25a and 25b which intersect eachmounting bore 26. The bores 25a and 25!! form part of a fuel system forsupplying fuel under pressure to and for conducting fuel from theinjectors. In the present instance, the bore 25a supplies fuel under acontrolled pressure to the injector 30., and the bore 25b conducts fuelfrom the injectors to drain.

The fragment of the engine illustrated in'FIG. 1 also includes a rockshaft 27 extending lengthwise of the engine and having a plurality ofrocker arms mounted thereon, each indicated at 28, and there being onefor each injector. Each rocker arm 28 is adapted to be rocked on theshaft 27 by means such as a push rod (not shown) and an engine drivencam (also not shown). Movement of each rocker arm 28 is transmitted toits associated injector 30 by a link 29.

The Embodiment Shown in FIGS. 2 -8 Referring now to FIGS. 2--8,inclusive, the injector 30 comprises an elongated injector body 32having a plunger bore 33 therein and including a nozzle having at leastone and preferably a plurality of nozzle openings 36 therein throughwhich fuel is injected into the associated cylinder. A plunger,indicated generally at 37, is reciprocably mounted in the bore Theinjector body 32, in the present instance, comprises a generallycylindrical body member 41, a barrel member 42,

and a nonle member 45 provided with the nozzle openings 36 are arrangedin end-to-end relation. The end facesQindicated endto-end relatiomatubularretainer 50 is providedTo this end, the upper end of the retainer50 is internally threaded, as at 51, for engagement with-extemal threads52 on the lower end of the body member 41, as viewed in FIG. 2. Thelower end of the retainer 50 is provided with an internal flange 53 forengaging an annular, radially outwardly extending flange 46,47 of thebody member 41, barrel member 42 and nozzle member 45 are held inabutting engagement. A pin 55 FIGS. 3

and 6 6) assures accurate circumferential alinement between I the bodymember 41 and barrel member 42.

As heretofore mentioned, the injector body 32 is provided with a bore 33for receiving the plunger '37. The bore 33 includes a portion 66 in thebarrel member 42 and a portion 67 I 57 on the nozzle member 45. Thus,when the retainer 50 is threaded onto the body member 41, the end faces43,44 and in the body member 41, having various diameter counterbores,the portion 67 being'of somewhat larger diameter than v the portion 66in the barrel member 42 so that the up'perpart of the plunger 37 doesnot contact the body member 41. The interiorofthe nozzle memberconstitutes a continuation of the plunger bore 33.'- I

The plunger 37, which comprises a fuel injection means in the injector30, includes a fuel injection and'control portion 71, and a sleeveportion-72', the lower end of which, indicated 7 at 73', is secured tothe upper end of the portion 71 of the an abutment for one end of a coilspring 77 disposed around the sleeve portion 72. The other or lower endof the coil spring 77 bears against a shoulder 78 and defined by a largecounterbore 79 in the upper end of the body member 41. The spring 77 isnormally under compression and serves to urge the plunger 37 away fromthe nozzle openings 36.

Movement of the plunger 37' toward the nozzle opening 36 is effected bythe rocker arm 28 acting through the link 29. The lower end, indicated.at 83 (FIG. '2), of the link 29. is spherically formed and engages acomplementally shaped seat 84 in the upper end of the portion 71 of theinjector plunger 37. The upper end, indicated at 86, of the link 29, issimilarly As heretofore mentioned, the injector body 32 has a fuelpassage therein, indicated generally at 90, adapted to be connected to asource of fuel under pressure and having a connection for supplying fuelto a fuel injection chamber in the injector for injection therefromthrough the nozzle openings 36 into the associated cylinder. To connectthe passage'with the source, theinjector body 41 is provided with anexternal annular groove 91 positioned to register with the fuel supplyline 25a in the cylinder head 24,'as illustrated in FIG. 1, when theinjector is fully seated in'its mounting bore 26. A plug 92, having abalancing orifice 93, extends inwardly from the groove 91, with theorifice 93 communicating withthe upper end of a vertical bore 94 in theinjector body member 41. The vertical bore 94 forms part of the fuelpassage and the balancing orifice 93 in the plug 92 comprises one'end ofthe fuel passage. The orifice 93 serves to meter the flow of fuelentering the'fuel passage in the injector. A filtering screen 95'may bemounted in the groove 91 over the plug 92 to prevent foreign particlesfrom entering the fuel passage. A pairfof smallergrooves 97 and'98 maybe providedon each side of the groove 91 for receiving seals, such asO-rings shownfin FIG. 1, to prevent leakage from the lower anduppersides, respectively, of the groove9l.

Assuming the injector plunger 37 is in the position thereof .illustratedin FIG. 2, which is the position it would occupy at proceeds downwardlyin the'bore 94 and into the upper end of another vertical bore 109 inthe barrel member 42. Theflow then enters aportion 112 ch diagonal bore112,113 in the barrel 42, which intersects the portion 66 of the plungerbore 33. Before reaching the portion 113, the flow passes through anannular space 114 in the plungerbore 33,defined by an annular groove 115around the portion 71 of the injector plunger 37. On passing through thespace 114,jthe fIow' enters the portion 113 of the diagonal bore 112,113and then flows into another vertical bore 117 in the barrel member'42.On entering the vertical bore 117, the flow splits, part of the flowproceeding downwardly in'the portion of the bore 117 below theintersection of the portion 113" of the bore 112,113 therewith. Orireaching thelower end of the bore 117, this portion of the flow entersan enlarged portion 118 of the bore 117 and then passes around a checkball 119 mounted in the portion 118. The seat forthe check ball 119 isprovided by a shoulder 123 above the ball and defined by the enlargedportion 118 of the bore 117'. The flow thenpas'ses around the ball 119and enters a shallow arcuate groove '122 FIGS. 3, 4, 5 and 8) in the endface 46 of the barrel member 42.

From the arcuate groove 122, the flow enters the lower end of anothervertical bore 124 (FIGS. 3, 4, and 5) in the barrel member 42 andcontinues upwardly therein. A plug 126 having an orifice 127 therein ismounted in the bore 124 for restricting the flow through this portion ofthe fuel passage.

From the upper end of the bore 124, the flow enters a portion 128 of atransverse bore 128,129 in the barrel member 42, which intersects theportion 66 of theplunger bore 33. Be-

fore reaching the portion 129, the --flow enters an annular space 132 inthe portion 66 of the plunger bore 33, defined by another groove 133 inthe portion 71 of the injector'plunger.

From the annular space 132, the flow enters the lower end of an inclinedbore 134 (FIGS. 3 and 6) in the barrel member 42 and proceeds upwardlytherein and in another inclined bore 136 in the body member 41 to ashort, transverse bore 137 in the body member 141. The bore 137 opensinto a groove 138 around the body member 41, which communicates with thedrain ,or return bore 25b (FIG. 1) in the cylinder head 24 of theengine. A shallow groove 139 is provided in the injector body 41 abovethe groove 138 for receiving a seal, such as an O-ring, to prevent fuelleakage from the upper side of the groove 138.

Thus, the aforementioned series of interconnected bores through theinjector body' 32, beginning with the balancing orifice 93 andterminating with the lower portion of the vertical bore 124 below therestriction 127, comprise the fuel passage or passages through theinjector body that are adapted to be connected to a source of fuel underpressure, namely the fuel supply bore 25a; The flow through such passageserves, in part, to purge the injector of gases that may haveaccumulated in the passage.

As heretofore mentioned, the fuel passage in the injector body 32 alsoincludes a branch portion having its opposite ends connected to the fuelpassage. Thus, upon entering the portion of the vertical bore 117 (FIG.2) above the bore portion 113, which comprises one end of the branchportion, the flow proceeds upwardly in the bore. The flow thereafterenters the lower end of a counterbore 142 of the vertical bore 117 andacts against one face, in this instance the lower face 143, of a piston144 reciprocably mounted in the counterbore 142. The intersection of theupper end of the bore 117 with the counterbore 142 definesa shoulder 146comprising a stop for limiting downward movement of the piston 144 inthe counterbore 142. In FIG. 7, the piston 144 is shown engaged with theshoulder 146.

An arcuate groove 147 (FIGS. 3, 4 and 8) in the upper end face 44 of thebarrel member 42 has one end thereof intersecting the upper end of thecounterbore 142. The opposite end of the groove 147 intersects the upperend of another vertical bore 148 extending downwardly in the barrelmember 42. The lower portion of the bore 148 intersects the otherportion 129 of the transverse bore 128,129 and hence communicates withthe annular space 132 defined by the plunger groove 133. The portion 129of the transverse bore 128,129 comprises another end of the branchportion. The. space 132, is, of course, connected to the drain bores134, 136 and 137 (F IG. 6) when the plunger 137 is in the position shownin FIGS. 2, 4 and 8. Consequently, the space above the upper or oppositeface, indicated at 151, of the piston 144 also communicates with thedrain bores 134, 136 and l37. The branch portion of the fuel passage 90thus comprises the portion of the vertical bore 117 above the transversebore 112,113, together with the counterbore 142, arcuate groove 147,vertical bore 148 and portion 129 of the transverse bore 128,129. Inaddition, the piston 144 and counterbore 142 comprise piston andcylinder means in the branch portion of the fuel passage.

In the injection cycle, the piston 144 will be moved upwardly in itsbore 142 by an amount dependent on the amount of fuel flowing upwardlyin the vertical bore 117. Such movement will continue as the plunger 37begins to move upwardly in its bore until the groove 115 moves past theadjacent end of the portion 113 of the diagonal bore 112,113. When thiso'ccurs, the flow of fuel through the portion 113 of the diagonal bore112,113 is interrupted. Consequently, no further upward movement of thepiston 144 in its bore 142 will occur. During upward movement of thepiston 144, fuel in the space above the upper end face 151 thereof isdisplaced through the connected bores 134, 136 and 137 to drain.

Continued upward movement of the plunger 37 in its bore 33 causes thegroove 133 to move beyond the inner ends of the portions 128 and 129 ofthe transverse bore 128,129 (FIG. 8), thus interrupting communicationtherebetween. Shortly after this occurs, the groove 115 will move overand provide communication between the inner end of a short transversebore 156 in the barrel member 42 below the transverse bore 128,129. Thegroove 115 is of sufficient length so that when it establishescommunication with the bore 156, it is also in communication with theportion 112 of the diagonal bore 112,113. The bore 156 is intersected bythe lower end of the bore 148. At about the same time or shortly afterthe groove 115 moves out of communication with the inner end of thetransverse bore 156, a shoulder 157 (FIGS. 7 and 8) defined by a reduceddiameter portion 158 at the lower end of the plunger 37, moves past anduncovers a small transverse bore or feed hole 162 in the barrel member42. The inner end of the feed hole 162 intersects the portion 66 of theplunger bore 33 and the outer end of the feed hole 162 intersects thelower end of the vertical bore 124 below the plug 126.

Thus, as the plunger 37 moves upwardly in its bore from the positionthereof illustrated in FIGS. 2, 4 and 6 to the position thereofillustrated in FIGS. 7 and 8, upward flow of fuel in the bore 117 isshut off and thus upward movement of the piston 144 in its bore isterminated. Thereafter, communication is established between the portion112 of the diagonal bore 112,113 and the transverse bore 156 so that thepressure of the fuel in the portion 112 is applied to the upper end face151 of the piston 144. Subsequently, the feed hole 162 (FIG. 2) isuncovered so that communication is established between the lower end ofthe vertical bore 124 and the upper portion, indicated at 163 (FIGS. 7and 8), of a fuel injection chamber 165, the portion 163 being definedby the reduced diameter portion 158 of the plunger and the plunger bore66. Under these conditions, the piston 144 moves downwardly in its bore.Such movement causes a quantity of fuel equal to that displaced bydownward movement of the piston to be forced through the feed hole 162into the portion 163. The feed hole 162 thus comprises a connectionbetween the fuel passage and the fuel injection chamber 165, and thespace between the lower face 143 of the piston 144 and the shoulder 146constitutes another chamber 166, the function of which will behereinafter described. The quantity of fuel transferred to the portion163 is subsequently forced by movement of the plunger 37 to the lowerportion, indicated at 167, of the fuel injection chamber 165, theportion 167 being defined by the interior of the nozzle member 45 andthe tapered lower end 104 of the injection plunger 37. Such transfer tothe portion 167 of the fuel injector chamber occurs through a smallannular space 168 between the reduced diameter portion 158 of theplunger and the adjacent wall, indicated at 169, of the nozzle member45. Continued downward movement of the plunger 37 causes the fuel in theportion 167 to be injected into the cylinder through the nozzle openings36.

The orifice 127, the portion of vertical bore 124 thereabove, portion128 of transverse bore 128,129, annular space 114, inclined bore 134 inthe barrel member 42, and the connected inclined and transverse bo'res136 and 137, respectively, in the body member 41, comprise anotherconnection between the fuel passage and drain.

As mentioned above, the' quantity of fuel supplied to the fuel injectionchamber 165 is equal to that in the chamber 166 or that displaced bydownward movement of the piston '144 from an elevated position. thereofin its bore 142 to its lowest position in the bore. However, since themaximum extent of upward movement of the piston 144 in its bore 142 isdetermined by the end face 43 of the body member 41, the maximum volumeof the chamber 166 is limited. The end face 43 of the body member 41thus comprises stop means for limiting movement of the piston 144 in onedirection, namely, in an upward direction as viewed in FIGS. 2 and 7.Since the maximum stroke of the piston 144 is limited, a quantity offuel greater than that contained in the chamber 166, when the piston 144is in its uppermost position, cannot be transferred to the fuelinjection chamber 165 for injection into the associated cylinder. Thechamber 166 thus comprises a fuel limiting chamber.

From the foregoing, it will be apparent that the quantity of fuelsupplied to the cylinders of an engine utilizing a set of the injectors,such as the injector illustrated in FIGS.28, cannot be increased beyonda predetermined maximum and hence the maximum power output of the enginecannot be increased. Moreover,'there is no simple way of tampering withthe in jectors to increase the fuel charge delivered to the cylindersbeyond the predetcrmined'maximum.

As heretofore mentioned, the check ball 119 is provided in the lower endof the vertical bore 117. Such check ball serves to minimize aeration offuel in the injector and to prevent pressure waves from passing throughthe fuel passage 90 of the injector to the common supply bore 25a wheresuch wave could possibly adversely affect the metering of fuel inadjacen injectors.

The Embodiment Shown in FIGS. 9 14 In FIGS. 914, inclusive, a modifiedform of fuel injector through which fuel is injected into the associatedcylinder. A

plunger, indicated generally at 187,,is reciprocably mounted in the bore183. i

The injector body 182, in the present instance, comprises a generallycylindrical body member 192 and a nozzle member 193 arranged inend-to-end relation. For holding the body member 192 and nozzle member193 in end-to-endabutting relation, a tubular retainer 195 isprovidedfilhc upper end of the retainer 195 is internally threaded asat196 for engage ment with external threads 197 on the lower end of thebody member 192 as shown in FIGS. 9,12, 13 and 149T he lower end of theretainer 195 is provided with an internal flange 198 for engaging anannular, radially outwardly extending flange 199 on the nozzle member193. Thus, when the retainer 195'is threaded onto the lower end of thebody member 192, the

nozzle member 193 is held in abutting end-to-end engagement therewith. vg I g The plunger bore 183,in the present instance, has the samediameter throughout the length of the body member 192, and the interiorof the nozzle member 193 constitutes a continuation of the plunger bore183 but of a reduced diameter.

The plunger 187, which comprises a fuel injection means,

may be provided with a spring retainer (not shown) providing a seat forthe upper end of acoil spring 200. The lowerend of the coil spring 200may bear against the upper end face, indicated at 201, of the bodymember 192. The coil spring tends to urge the plunger 187 away from thenozzle openings 186,

movement of the plunger 187 being controlled by an engine driven cam(not shown) and interconnecting linkage (also not shown). I

As heretofore mentioned, the injector body member 192 has a fuel passagetherein, indicated generally at 205, adapted to be connected to a sourceof fuel under pressure and'having 1 the groove 206, and a plug 207having a balancing orifice 208 therein is threaded into the counterboredouter end of the transverse bore 211. The bore 211 forms part of thefuel passage 205 and intersects the plunger bore 183. i

The balancing orifice 208 in the plug 207 thus comprises one end of thefuel passage 205 and serves to meter the flow of fuel entering thepassage. A filtering screen (not shown) may bemounted in the groove 206exteriorly of the plug 207 to prevent foreign particles from enteringthe fuel passage. A

pair of smaller annular grooves 213 and 214 may be provided on each sideof the groove 206 for receiving seals, such as rings, to prevent leakagefrom the groove 206.

Assuming the injector plunger 187 is in the position thereof illustratedin FlGS. 9, 11 and 12, the tapered lower end, in-

dicated at 216, of the plunger is shown as seated on a comple-' mentallyshaped inner surface 217 in the nozzle member 193. When the plunger 187is so positioned, fuel under pressure will flow through the balancingorifice 208 in the plug 207 and thence into the transverse bore 21 1,inthe injector body' member 192. The fuel then enters and annular space222 inthe plunger bore 183, the space 222 being provided an annulargroove 223 in the injector plunger 187. On entering the annular space222, the flow splits, a part thereof entering a portion 226 of atransverse bore 226,227 (FIGS. 9 and in the injector body 192, whichintersects the plunger bore 183. From the portion 226, the flow proceedsdownwardly in a vertical borej229 in the body member 192 and past a feedhole 230 which extends inwardly from thebore 229 to the plunger bore183. The innerend of the feed hole 230 is closed by the plunger 187 atthis time.

On reaching the lower end of the vertical bore 229', the flow passesthrough a shallow groove 232 (FIGS. 10, '12 and 14) in the lower endface, indicated at 233, of the body member 192 and then flows upwardlyin another vertical bore 234 (FIGS. 10 and 12) in the injector bodymember 192. On reaching the upper end of the bore 234, the flow passesinwardly in a portion 236 of another transverse bore 236,237 (FIGS. 10and 12) in the body member 192. The transverse bore 236,237 intersectsthe plunger bore 183 at a point above the transverse bore 226,227. Fromthe portion 236 of the transverse bore 236,237, the flow enters anannular groove 239 (H08. 11 and 12) in the plunger 187. V

From the groove 239, the flow proceeds outwardly through another short,transverse bore 242 (FIGS. 10, 11 and 12) in the body member 192 andthen through a restriction provided upper side of the groove246 when'theinjector body is mounted in its bore in the cylinder head of the engine.The

seal in the groove 214, heretofore described, prevents leakage from thelower side of the groove 24.6. i

Thus, the aforementioned series of interconnected bores through theinjector body 182, beginning with the orifice 208 in the plug 207 andextending to the feed hole 230, comprise a fuel passage or passagesthrough the injector body 182 adapted to be connected to a-source offuel under pressure,

namely the fuel supply bore 25a. The flow through such provided with atransverse bore 211 extending inwardly from g passages serves to purgethe injector of any gases which may accumulate in the passages.-

As heretofore mentioned, the fuel passage in the injector body 182 alsoincludes a branch portion having its opposite ends communicating withthe fuel passage. Thus, upon entering. the annular space 222, theother'part of the flow passes into thportion 227 of the transverse bore226,227, the portion 227 comprising one end of the branch portion. Fromthe portion 227, the flow proceeds downwardly in a vertical bore 252 inthe injector body member 192. The lower portion of the bore 252 iscounterbored as at 253 to constitute a cylinder, with a piston in theform of a ball 254 reciprocably mounted in the counterbore 253. Theupper end of the counterbore 253 defines a shoulder 256 forlimitingupward movement of the ball. 254 in the counterbore 253. In FIG. 13, theball is shown engaged with the shoulder 256. i

A groove 257'(F1GS. 10 and 13) in the lower end face 233 of the bodymember 192 extends from the lower end of the counterbore 253 to anothervertical bore 258 (F168. 10 and 12) in the body member. 192. The flowproceeds upwardly in the vertical bore 258 and, on reaching the upperend of the bore, flows inwardly in the portion 237 of the transversebore 236,237. The inner end of the transverse bore portion 237communicates with the groove 239 (FIG. 12) in the plunger 187.

Fuel displaced'from the branch portion thus unites with the ,flowthrough the fuel passage 205 at the groove 239 and the flow thenproceeds outwardly through the transverse bore 242 (FIG. 11) and orifice243 to drain. The bore portion 237 thus comprises the other end of thebranch portion of the fuel passage in the injector body 182.

The branch portion of the fuel passage 205 thus comprises the portion227 of the transverse bore 226,227, vertical bore 252, groove 257 (FIGS.10 and 13), vertical bore 258 and portion 237 of transverse bore236,237. In addition, the ball 254 and counterbore 253 constitute pistonand cylinder means in the branch portion of the fuel passage.

In the injection cycle, the ball 254 will be moved downwardly in itsbore 253 by an amount dependent upon the amount of fuel flowingdownwardly in the vertical bore 252. During downward movement of theball 254, fuel in the space below the ball 254 is displaced through thegroove 257, vertical bore 258 and transverse bore portion 237 to drainby means of the transverse bore 242 and orifice 243 (FIG. 11). Downwardmovement of the ball 254 continues as the plunger 187 begins to moveupwardly in its bore, from the position thereof illustrated in FIGS. 9,11 and 12 toward the position thereof illustrated in FIGS. 13 and 14,such movement of the ball continuing until the groove 223 moves out ofcommunication with the inner ends of the portions 226 and 227 of thetransverse bore 226,227. When this occurs, the downward flow of fuelthrough the vertical bore 252 is interrupted. Consequently, no furtherdownward movement of the ball 254 in its bore 253 will occur.

Continued upward movement of the plunger 187 in its bore 183 causes thegroove 239 to move out of communication with the transverse boreportions 236 and 237 and also out of communication with the inner end ofthe transverse bore 242. Consequently, the flow to drain is cut off.

Further upward movement of the plunger 187 in the bore 183 toward theposition thereof illustrated in FIGS. 13 and 14 causes a shoulder 262defined by a reduced diameter portion 263 on the lower end of theplunger 187 to move past and uncover the feed hole 230. As the feed hole230 is uncovered, the groove 223 moves over and provides communicationbetween the inner end of a short transverse bore 264 (FIGS. 12 and 14)in the body member 192, below the transverse bore portion 237. At thesame time that the feed hole 230 is uncovered, an annular groove 267 onthe plunger 187 moves into communication with the inner ends of a pairof portions 272 and 273 (FIGS. 9 and 13) of another transverse bore272,273 in the body member 192, the bore 272,273 intersecting theplunger bore 183 below the transverse bore portions 226 and 227. Theouter endof the bore portion 272 intersects the vertical bore 229 (FIG.13) and the outer end of the bore portion 273 intersects the verticalbore 252.

Under these conditions, the ball 254 begins to move up wardly in itsbore 253. Since the space between the ball 254 and shoulder 256communicates with the feed hole 230 through the bore 252, portions 272and 273 of the transverse bore 272,273, groove 267, and vertical bore229, a quantity of fuel equal to that displaced by upward movement ofthe ball 254 is forced through the feed hole 230 into the portion 376 of276 of a fuel injection chamber 277. The feed hole 230 thus comprises aconnection between the fuel passage 205 and the fuel injection chamber277, and the space between the ball 254 and shoulder 256 constitutesanother chamber 278, the function of which will be hereinafterdescribed. In addition, the portion of the vertical bore 229 below thefeed hole 230, groove 232, vertical bore 234, and portion 236 of thetransverse bore 236,237, groove 239, transverse bore 242 and orifice 243in the plug 244, comprise another connection between the fuel passageand drain.

The quantity of fuel transferred to the portion 276 of the fuelinjection chamber 277 is subsequently forced by movement of the plunger187 toward the lower portion, indicated at 282, of the fuel injectionchamber 277, the portion 282 being defined by the interior of the nozzlemember 193 and the tapered lower end 2160f the injection plunger 187.Such transfer of fuel to the portion 282 of the fuel injection betweenthe reduced diameter portion 263 of the plunger and the adjacentwall,.indicated at 284, of the nozzle member 193.

As mentioned above, the quantity of fuel supplied to the fuel injectionchamber 277 is equal to that displaced by upward movement of the ball254 from a lower position thereof in its bore 253 to an elevatedposition in the bore. However, since the maximum extent of the downwardmovement of the ball 254 is determined by the upper end face, indicatedat 286 in FIGS. 9 and 13, of the nozzle member 193, the maximum volumeof the chamber 278 is limited. The end face 286 of the nozzle member 193thus comprises stop means for limiting movement of the ball 254 in onedirection, namely, in a downward direction as viewed in FIGS. 9 and 13.Since the maximum degree of movement or stroke of the ball 254 islimited, a greater quantity of fuel than that contained in the chamber278, when the ball 254 is in its lowermost position, cannot betransferred to the fuel injection chamber 277 for injection into theassociated cylinder. The chamber 278 thus comprises a fuel limitingchamber.

From the foregoing, it will be apparent that the quantity of fuelsupplied to the cylinders of an engine utilizing a set of injectors,such as the injector illustrated in FIGS. 9-14, cannot be increasedbeyond a predetermined maximum and hence the maximum power output of theengine cannot be increased. Moreover, there is no simple way oftampering with the injectors to increase the fuel charge delivered tothe cylinders beyond the predetermined maximum.

The Embodiment Shown in FIGS. 15-18 In FIGS. 15- 18, inclusive, anothermodified form of fuel injector embodying the features of the inventionis illustrated.-

The injector therein illustrated is adapted to be mounted in an injectorbore having the same configuration as the bore 26 in the cylinder head24 for the injector 30 illustrated in FIG. 1.

The injector shown in FIGS. 15 18 comprises an elongated body 302 havinga plunger bore 303 therein and including a nozzle having at least oneand preferably a plurality of nozzle openings 306 therein through whichfuel is injected into the associated cylinder. A plunger, indicated at307, is reciprocably mounted in the bore 303.

The injector body 302, in the present instance, comprises a generallycylindrical body member 312 and a nozzle member 313 arranged inend-to-end relation. For holding the body member 312 and nozzle member313 in abutting relation, a tubular retainer 315 is provided. The upperend of the retainer 315 is threaded as at 316, on the lower end of thebody member 312 as shown in FIGS. 15 and 16. The lower end of theretainer 313 is provided with an internal flange 318 for engaging anannular, radially outwardly extending flange 319 on the nozzle member313. Thus, when the retainer 315 is threaded onto the lower end of thebody member 312, the nozzle member 313 is held in abutting, end-to-endengage- I ment therewith.

The plunger bore 303, in the present instance, has the same diameterthroughout the length of the body member 312, and the interior of thenozzle member 313 constitutes a continuation of the plunger bore 303 butof a reduced diameter.

The plunger 307, which comprises a fuel injection means, may be providedwith a spring retainer (not shown) providing a seat for the upper end ofa coil spring 308. The lower end of the coil spring 308 may bear againstthe upper end face, indicated at 321, of the body member 312. The coilspring tends to urge the plunger 307 away from the nozzle openings 306,movement of the plunger 307 being controlled by an engine driven cam(not shown) and interconnecting linkage (also not shown).

chamber 277 occurs through a small annular space 283 As heretoforementioned, the injector body member 312 has a fuel passage therein,indicated generally at 325, adapted to be connected to a source of fuelunder pressure and having a connection for supplying fuel to a fuelinjection chamber in the injector for injection therefrom through thenozzle openings 306 into the associated cylinder. To connect the fuelpassage with the source. the body member 312 is provided with anexternal annular groove 326 adapted to be connected with a source offuel under pressure, such as the fuel supply line 25a in the cylinderhead 24, when the injector is fully seated in its mounting bore 26. Thebody member 312 is provided with a transverse bore 331 extendinginwardly from the groove 326, and a plug 327 (FIG. 18) having abalancing orifice 328 therein is threaded into the counterbored outerend of the transverse bore 331. The bore 331 forms part of the fuelpassage 325 and intersects the plunger bore 303.

The balancing orifice 328 in the plug 327 thus comprises one end of thefuel passage 325 and serves to meter theflow of fuel entering thepassage. A filtering screen (not shown) may be mounted in the groove 326to preventforeign particles from entering the fuelpassage; A pair ofsmaller annular grooves 333 and 334 may be provided on each side of thegroove 326 for receiving seals, such as -rings, to prevent leakage fromthe groove 326.

Assuming the injector plunger 307 is in the position thereof theinnerend of a short, transverse bore 344, (FIGS. 15 and 16) in theinjector body member 312. The flow then proceeds outwardly inthe'transverse' bore 344 to a juncture with the upper endof a verticalbore 346 and the lower end of an inclined bore 347 in the body member312 where the flow splits. I r

7 Part of the flow proceeds downwardly in the bore 346 and, on reachingthe lower end of the bore, enters one end of a semicircular groove 348(FIGS. 15, 16 and 17) in the lower end face, of the body member 312. Onreaching the opposite end of the groove .348, the flow enters the lowerend of another vertical bore 349 in the body member 312 and flowsupwardly therein past afeed hole 350 which extends inwardly Iillustrated in FIGS. and, 18, the tapered, lower end, in-

.the ball 367 is shown engaged with the shoulder 368.

The upper end of the counterbore 366 is threaded to receive a plug 372,the plug 372 being positioned in the coun' terbore 366 above the portion353 of the transverse bore, 352.353. The outer end of the transversebore portion 353 intersects the counterbore 366 so that the latter alsocommunicates with the groove'357 in the plunger 307 when the plunger isin the position thereof illustrated in FIG. 15.

Fuel displaced from the branch portion thus unites with the flow throughthe fuel passage 325 at the groove'357 and then proceeds outwardlythrough the transverse bore 358 (FIG. 18) and orifice 362 to drainQThetransverse bore portion 353 thus comprises the other end of the branchportion of the fuel passage in the injector body 312.

The branch portion of the fuel passage 325 thus comprises" the inclinedbore 347, counterbore 366 and portion 353 of transverse bore 352,353. Inaddition, the ball 367 and counterbore 366 constitute piston andcylinder means in the branch portion of the'fuel passage.

In the injection cycle, the ball 367 will be moved upwardly in its bore366 by an amount dependent uponlheamount of fuel flowing upwardly in theinclined bore 347. During upward movement of the ball 367 fuel in thespace above the ball is displaced. through the portion 353 of thetransverse .bore

352,353 to the groove 357 in the'plunger 307, from whence it flows todrain through the transversejbore 358 (FIG. 18) and orifice 362. Upwardmovement of the ball 367 in its bore'co'm tinues as the plunger 307begins tomove upwardlyin its bore 303, from the position thereofillustrated in FIGS. 15 and 18 toward the position thereof illustratedin FIG. 16, such movement of the ball continuing until the groove 357moves out of communicationwith the inner ends of the portions 352 andfrom thebore 349 to the plunger bore 303. The innerend of 40 353 of thetransverse bore 352,353. When this occurs, the

the feed hole 350 is closed by the plunger 307 at this time.

on reaching the upper end of the vertical bore 349, the flow then passesinwardly in a portion'352 of a transverse bore 352,353 in the bodymember 312. The transverse bore 352,353 intersectsthe plunger bore 303at a point above the transverse'bore 331. From the portion 352 of thetransverse bore 352,353, the flow enters another annular groove 357 inthe plunger 307.

From the groove 357, the flow proceeds outwardly through ashorttransverse bore 358 (FIG. 18) in the body m'ember312 and thenpasses'through a restriction provided'byan orifice 362 in a plug 363mounted in the outer end of the transverse bore 358. The orifice 362opens into a groove 364 around the body member 312, which is adapted tocommunicate with a drain such as the return bore 251: in the cylinderhead 24 illustrated in FIG. 1. A shallow groove 366 is provided aroundthe injector body member 312 above the groove 364 for receiving a seal,such as an (king, to prevent leakage from the upper side of the groove364 when the injector body is mounted in its fuel passage or passagesadapted to be connected to a source of fuel under pressure such as thefuel supply bore 25a. The" flow through such passages serves to purgethe injector of any gases which may accumulate in the passages.

As-heretofore mentioned, the fuel passage in the injector body 302 alsoincludes a branch portion having its opposite ends communicating withthe fuel passage. Thus, upon flow of fuel to drain is interrupted.Consequently, no further upward movement of the ball 367 in its bore 366will occur.

7 Continued upward movement of the plunger 307 in its bore 303 causesthe groove 343 to move out of communication with the inner end of thetransverse bore 344 and also causes the groove 343 to move intocommunication with the inner end of another transverse [bore 373 in theinjector body member 312. The bore 373 is positioned somewhat below thetransverse bore 352,353. 7

At the same time that the groove 343 moves into communication with theinner end'of the bore 373. a shoulder 374 defined by a reduced diameterportion 376 onthe lower end of the plunger 30'] moves past and uncoversthe feed hole 350.

Under these conditions, fuel under pressure from the groove 343 flowsoutwardly in the bore'373 and into the counterbore 366 at a point abovethe ball 367. Consequently, the ball 367 is caused to move downwardly inits bore toward the shoulder 368. Since the space between the' ball 367and shoulder 368 communicates with the feed hole 350 through fuelinjection chamber'378, and the space'between the ball 367 and theshoulder 368 constitutes another chamber 381 (FIG. 15), the function ofwhich will be hereinafter described. In addition, the portion of thevertical bore 349 above the feed hole 350. the portion 352 of thetransverse bore 352,353 the groove 357, the transverse bore 358 andorifice 362 comprise another connection between the fuel passage anddrain.

The quantity of fuel transferred to the portion 377 of the fuelinjection chamber 378 is subsequently forced by movement of the plunger307 toward the lower portion, indicated at 382, of the fuel injectionchamber 378, the portion 382 being defined by the interior of the nozzlemember 313 and the tapered lower end 336 of the injector plunger 307.Such transfer of fuel to the portion 382 of the fuel injection chamber378 occurs through a small annular space 383 between the reduceddiameter-portion 376 of the plunger 307 and the adjacent wall indicatedat 384 of the noule member 313; e

As mentioned above, the quantity of fuel supplied to the fuel injectionchamber 378 is equal to that displaced by downward movement of theball367 from an upper position thereof in its bore 366 to a lower positionin the bore, However, the maximum extent of upward movement of the ball367 is determined by an extension or stem 387-on the lower end of theplug 372. Consequently, the maximum volume of the chamber 381 islimited. Moreover, the'ex'tension 387 comprises stop means for limitingmovement of the ball 367 in one direction, namely, in an upwarddirection as viewed in FIGS. and 16. Since the maximum extent ofmovement of the ball 367 is limited, a greater quantity of fuel thanthat contained in the chamber 381, when the ball 367 is in its uppermostposition, cannot be transferredto the fuel injector chamber 378 forinjection into the associated cylinder. The chamber 381 thus comprises afuel limiting chamber.

As heretofore mentioned, the plug372 is threaded into-the upper end ofthe counterbore366. The position of the plug 372 may be adjusted to varythe maximum volume of the chamber 381. The upperend of the counterbore366 is enlarged and threaded as at388 to receive another plug 389.

The plug 389 thus renders the plug 372 inaccessible, and the plug 389 isin itself inaccessible since it is in the upper end face 321 of theinjector body member 312 and is thus covered by the lower end of theplunger spring 308. However, the position of the plug 372 can beadjusted if .need be in order to adapt the injector to the maximum fuelrequirements of a particular engine.

From the foregoing, it will be apparent that the quantity of fuelsupplied to the cylinders of anengineutilizing a set of in jectors, suchas the injector illustrated in FIGS. 15-48, cannot be easily increasedbeyond a predetermined maximum and hence the maximum power output of theengine likewise can not be increased. Moreover, there is no simple wayof tampering with the injectors to increase the fuel charge delivered tothe cylinders beyond the predetermined maximum. We claim:

1. An injector for injecting fuel into a cylinder of an internal"combustion engine, comprising an injector body having a fuel passagetherein and a fuel injection chamber having an opening adapted tocommunicate with said cylinder, said fuel passage being adapted to beconnected to a source of fuel under pressure and having a connectionwith said fuel injection chamber, means for injecting fuel from saidfuel injection chamber through said opening into said cylinder, and apiston connected to said fuel passage and being shiftable in onedirection by the pressure of the fuel in said fuel passage by anamountproportional to said pressure during one portion of the operatingcycle of said injector to create a space connected to and receiving fuelfrom said passage, said piston being shiftable in the opposite directionby the pressure of the fuel in said passage during another portion ofthe operating cycle of said injector to transfer a quantity of fuelequal to the quantity of fuel in said space to said fuel injectionchamber for injection into said cylinder.

2. The injector of claim 1, including stop means for limiting movementof said piston in said one direction and consequently the maximum sizeof said space, a said stop means thereby limiting the maximum quantityof fuel injected into said cylinder during each operating cycle.

3. The injector of claim 2, in which said injector body includes a bodymember and a barrel member in end-to-end relation, said space beingprovided in said barrel member adjacent said body member, and said stopmeans comprises a portion of the end face of saidbody member adjacentsaid space.

cludes a branch portion, and said piston is mounted in said 4. Theinjector of claim 2, n-which said injector body includes a body memberand a nozzle member in end-to-end relation, said space being provided insaid body member adjacent said nozzle member, and said stop meanscomprises 'a portion of the end face of said nozzle member adjacent saidbody member. a

5. The injector of claim 2, in which said stop means comprises a plugthreaded into said injector body and extending into said fuel passage,the position of said plug being adjusta ble to permit adjustment of themaximum quantity of fuel supplied to said injection chamber. I

6. The injector of claim 2, including another stop means for limitingmovement of said piston in said opposite direction."

7. The injector of claim 6-, in which said second stop means comprises ashoulder in said fuel passage at one end of said space] 8. The injectorof claim 1, in which said fuel passage inbranch portion.

9. The injector of claim 8, in which said fuel injecting means isoperable to provide communication between one end of said branch portionand said fuel passage during said one portion of the operating cycle ofsaid injector, said fuel injecting means also being operable to providecommunication between the other end of said branch portion and said fuelpassage during said other portion'of the operating cycle of saidinjector.

10. The injector of claim 9, in whichsaid means for injecting fuel intosaid cylinder'com'prises a plunger reciprocably mounted in said injector"body, and said plunger selectively provides communication between theends of said branch portion and said fuel passage.

11. The injector of claim 9, in which said fuel passage includes anotherconnection adapted to extend to a drain, and said fuel injection meansis operable to establish flow through said other connection and toprovide said communication between said one end of said branch portionand said fuel passage during said one portion of the operating cycle ofsaid injector, said fuel injection means also being operable tointerrupt theflow through said other connection and to provide saidcommunication between saidother end of said branch portion and said fuelpassage'during said other portion of the operating cycle of saidinjector. I

12. The injector of claim II, in which said fuel injection meanscomprises a plunger reciprocably mounted in .said in jector body andhaving a pair of annular grooves therein, one of said grooves beingoperable when said plunger is in its position for said one portion ofthe operating cycle of said injector to provide said communicationbetween said one end of said branch portion and said fuel passage andsaid other groove being operable to establish flow through said otherconnection, said one groove also being operable when said plunger is inits position for said other portion of the operating cycle of saidinjector to provide said communication between said other end of saidbranch portion and said fuel passage and-said other groove beinginefi'ective to provide flow through said other connection.

13. The injector of claim 8, in which said fuel passage has anotherconnection adapted to extend to admin, and a restriction is provided insaid other connection for restricting the flow of fuel in said passageto said drain.

14. The injector of claim 13, in which said restriction is effectiveduring said one portion of the operating cycle of said injector tomaintain pressure in said branch portion tending to shift said pistonmeans in said one direction.

15. The injector of claim 13, in which said restriction is located insaid fuel passage adjacent said connection thereof with said fuelinjection chamber. 1

16. An injector for injecting fuel into a cylinder of an internalcombustion engine comprising an injector body having a fuel injectionchamber provided with an opening adapted to communicate with saidcylinder, a plunger reciprocably mounted in said injector body forinjecting fuel from said fuel injection chamber through said openinginto said cylinder, and piston and cylinder means in said injector bodyand having its nection thereof with said fuel injection chamber.

19. An injector for injecting fuel into a cylinder of an internalcombustion engine comprising an injector body having a fuel injectionchamber provided with an opening adapted to communicate with saidcylinder, a plunger reciprocably mounted in said injector body andoperable to effect injection of fuel from said fuel injection chamberinto said cylinder, said injector body also having a bore therein and apiston shiftably mounted in said bore and defining a fuel limitingchamber at one side of said piston, said fuel limiting chamber having apredetermined maximum volume determined by the position of said pistonwhen the latter is moved fully in one direction, and said injector bodyfurther having fuel passages adapted to connect said fuel limitingchamber with a source of fuel under pressure for supplying fuel to saidfuel limiting chamber to move said piston in said one direction duringone portion of the operatingcycle of said injector, said fuel passagesincludinga connection between said fuel limiting chamber and said fuelinjection chamber, and said piston being movable in the oppositedirection to transfer fuel from said fuel limiting chamber through saidconnection to said fuel injection chamber for injection into saidcylinder in response to movement of said plunger during another portionof the operating cycle of said injector.

20. The injector of claim 19, in which said fuel passages includeanother connection adapted to extend from the opposite side of saidpiston to a drain, and said plunger is operable during said one portionof the operating cycle of said injector to provide for flow through saidother connection.

21. The injector of claim 20, in which said one connection has a portioncommunicating with said other connection, and a restriction is providedin said portion for restricting flow through said portion to drain. 0740l 2

